Project Summary Despite having a dedicated copper export system, copper has been broadly toxic to bacteria since antiquity. Copper surfaces and tools significantly reduce nosocomial infections and during host mediated nutritional immunity (sequestering essential metals while bombarding bacterial with toxic metals), innate immune cells kill engulfed targets using copper, which is tightly regulated within the host. However, current research is limited regarding the overarching mechanisms of toxicity and the pathways used overcome copper stress in conjunction with the copper export system. The R35 that this proposal connects has the major focus of using Streptococcus pneumoniae to understand how copper is toxic and how bacteria overcome copper toxicity though the lens of the copper export operon. Furthermore, it seeks to find therapeutics that can target pathways poisoned by copper stress. The goal of this proposal is to characterize compounds that synergize with copper to kill bacteria, for which, we have preliminarily been successful. Here, Angela Rivera, an undergraduate in my laboratory, will test successful compounds determining how these compounds effect the metallo-burden of the bacteria, their efficacy in preventing bacterial growth, killing bacteria, and aiding macrophages to kill bacteria.